Vast Continent is a setting in the Pokémon Mystery Dungeon world. Covered in a rich lore that may or may not be partially explained in an outdated document. (Link)
(This world takes place in the following setting -- Link)

A continent on the smaller side created by Regis pulling land together to create a prison for the beast of dark magic, Eternatus. A land once ruled by a failing kingdom, buried under a false history set in by a horror-worshipping cult.
After countless struggles, the continent had finally freed itself from its false past, and peace came to the lands once more.

However, the continent has become a bit of a lure for ill-mannered trouble, and with more dungeons popping up, it will take a long time for peace to truly settle its way into Vast Continent.